The background description provided herein is for generally presenting the context of the disclosure. Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art or suggestions of the prior art by inclusion in this section.
The Network Controller Sideband Interface (NC-SI) specification was initially published in 2007. This NC-SI specification includes both the physical (electrical) and protocol aspects of NC-SI, which enable the connection of a Baseboard Management Controller (BMC), also referred to as a Management Controller (MC), to a set of Network Interface Controllers (NICs), e.g., for out-of-band remote manageability. The NC-SI specification allows a single BMC to be connected to multiple network controllers. In some cases, an NC-SI may include a point-to-point interface between a BMC and an Ethernet Controller (EC).
NC-SI traffic may include pass-through traffic and control traffic as Ethernet frames. Control traffic may include three different types of packets, Commands, Responses and Alerts. Configuration commands allow the BMC to gather information from an NIC (e.g., current link status). The BMC may also use commands to configure the NIC to send and receive Ethernet frames to and from the BMC. Responses include the response of an NIC to the command from the BMC. Alerts are called Asynchronous Events Notifications (AENs). They are alerts that can be sent asynchronously by the NIC to the BMC to indicate things such as a link status change or a change in operating system driver state. AENs provide a mechanism that allows the BMC to be informed of important changes without having to poll a network controller.